1. Field of the Invention
The present invention relates generally to improved apparatus and methods for closing perforations in body organs or blood vessels, which are alternatives to suturing; and, more particularly, relates to closure apparatus having application for closure of openings in body organs or blood vessel walls after invasive procedures in a patient's system have been performed.
2. Description of the Prior Art
There are several surgical procedures where it is necessary to puncture a blood vessel or other body organs in order to insert a catheter or other structures therein. The punctures are utilized for a number of reasons including, but not limited to, diagnostic procedures, radiological procedures, application of medication or therapeutic devices, coronary and peripheral angioplasties, thorascopic, laparoscopic, or endoscopic surgery, and the like. These procedures all involve making a puncture in body organs or in the wall of a blood vessel to be treated or used in treatment of the patient's system. The size of the puncture will vary depending on the procedure. It is common to utilize the femoral artery as the point of entry to the patient's body in many such procedures.
One type of procedure involves percutaneous puncture of the wall of a blood vessel, such as an artery, by insertion of catheter through which a guidewire is inserted. When the guidewire is positioned, a treatment device such as an inflatable balloon, is advanced coaxially along the guidewire to the point of the treatment. Often a sheath (cannula) is advanced with the treatment device. The proximal end of the sheath is retained outside of the skin of the patient, and can be utilized with a hemostatic valve to prevent blood flow from the artery through the sheath.
Sheaths generally are flexible tubes having thin walls and diameters in the range of up to about 21 F or more. Other procedures, such as may be encountered with use of endoscopes or other instruments, may utilize trocars for insertion. Typical trocar punctures can range from 2 mm to more than 15 mm in diameter, or from about 6 F to more than 45 F. Closure is typically accomplished using multiple levels of sutures. Once a procedure is completed and the sheath or other instrument is to be removed, the resulting wound aperture can be significant. Frequently, after conventional diagnostic or treatment procedures, whether of the peripheral circulation or coronary circulation systems, excessive bleeding occurs upon removal of the catheter or arterial sheath. In addition to bleeding, hematoma formation can be significant in many post-interventional procedures.
While excessive bleeding can be a problem with persons having a normal blood clotting response, there are patients who are at even higher risk of excessive blood loss. These would include patients who are utilizing anticoagulation medications which inhibit clotting, suffer from obesity, hypertension, or bleeding disorders, all of which raise the risk of excessive bleeding following removal of the sheath or other instruments.
Various procedures and devices have been developed to address the minimization of blood loss upon completion of the diagnostic or treatment procedure. A common practice has been to simply apply pressure to the location of the perforation. Pressure may be required for a relatively long time, such as one-half hour, followed by the patient being substantially immobilized for many hours. This treatment essentially relies on the self-healing characteristics of the patient and relies on normal clotting. Pressure treatment can suffer, however, from the excessive loss of blood and thrombosis formation. Further, the development of hematoma can be a significant problem.
Another post-intervention process to close off the puncture aperture has been to apply a collagen plug. This procedure does not avoid all of the blood loss and the placement of such material adds to the risk of thrombosis formation and development of an inflammatory auto-immune reaction.
Various devices have been developed to close or repair punctures or perforation openings in a patient's body. One relatively straight forward method and apparatus for closing wounds is the use of clips. One form of hemostatic clip is shown in U.S. Pat. No. 4,217,902 to March et al., and requires sufficient accessibility of the wound to allow operation of a clamping mechanism. The self-attaching hemostatic clip has wound flap-engaging teeth for holding the flaps of the wound together when activated. This device does not, however, deal directly with closing an aperture in the wall of a vascular vessel and would allow the subcutaneous formation of thrombosis. Another type of clip is shown in U.S. Pat. No. 5,478,354 to Tovey et al., which describes a clip fastener that is placed over a wound with its legs embedded in tissue about the wound. This clip also requires an external tool for closing the clip legs, and when used externally, suffers from a similar concern of allowing blood to gather below the surface of the skin. An alternative embodiment involves surgical fasteners that are inserted through the wound and for attachment under the wound. These clipping devices present the potential problems involving the increase in thrombosis.
Another device for closing or connecting blood vessels is illustrated in U.S. Pat. No. 5,234,448 to Wholey et al., wherein a plurality of microminiature barbs mounted on a support member are utilized to pierce the wall of a blood vessel to anchor the device in place. In a related patent, U.S. Pat. No. 5,383,897 to Wholey, a similar patch utilizing a plurality of small barbs to adhere to the wall of the artery is described. When used internally to the blood vessel, it appears that such a patch arrangement can present a situs for clot formation.
Various suturing systems have been developed. For example, U.S. Pat. Nos. 5,304,184 to Hathaway et al.; 5,364,408 to Gordon; and 5,462,561 to Voda, illustrate various forms of suturing devices that can place suture material in a body cavity to join the tissue surrounding an opening or wound made during a medical procedure. The deep suturing procedures are relatively complex, require dexterity and care in placing the needles, and generally are time consuming in the completion of the suturing procedure. The amount of time required to complete the suturing function can result in substantial blood loss, especially when dealing with arterial punctures. There is the further concern of accuracy of placement of the suture needles to provide an adequate engagement of tissue such that the completed suture will hold. Finally, the introduction of a suture material within the blood vessel may support the formation of clots.
In procedures such as thorascopic, laparoscopic or endoscopic surgeries, it is common to make entry to the patient's body with a trocar of suitable size to form an aperture large enough to insert the applicable instrumentation. Closure of such incisions quickly and efficiently cannot be accomplished with prior art clamping or suturing processes or equipment.